Method of removing cloud-forming materials from hydrocarbon oil



Patented Dec. 3, 1929 UNITED STATES 11011 or PENNSYLVANIA PATENT; OFFICE' CHARLES L. SUHB AND WINFIELD S. ZEHRUNG, OF OIL CITY, PENNSYLVANIA, AS-

SIGNOBS TO THE PENNZOIL COMPANY, OF OIL CITY, PENNSYLVANIA, AQCORPOR METHOD OF REMOVING CLOUD-FORMING MATERIALS FROM HYDBOCARBON OIL Ho Drawing.

Th' invention relates to a method of refining oi and more particularly to the treatment of the distillate of what is commonly known in the trade as dewaxed long residuum oil.

The distillates of dewaxed long residuum oil which have heretofore been used are those of the lighter range which have been free from cloud. The process of distillation, however, being continued to a certain point, a

lo heavy and more viscous distillate may be obtained which has a percentage of soft wax extremely small but sufiicient to givea cloudy efiect by which the usefulness of the product is so impaired that it has had slight commercial value and its separation into fractions has not been regarded as commercially justified. The object of this invention is to provide a simple and economical method of treatment of the heavy distillates of residuum oils whereby the cloud-forming materials contained therein and which have heretofore rendered these distillates of little commercial value may be entirely eliminated and thus enable such distillates to be rerun into heavier lubricants suitable for automotive purposes. By thepresent well known methods, crude petroleum oils have been subjected to fractional distillation to obtain the various distillates such as gasoline, kerosene, parafline,

etc., the residuum being known as long residuum oil. This residuum may or may notbe decolorized but in any case it is diluted with gasoline or naphtha'and then philled and centrifuged or allowed to settle in order to re move some of the contained wax after which the diluent is distilled ofi. The resulting product is known as dewaxed long residuum oil, which for convenience is herein termed product A and which is marketable as a lubricant. It is often desirable, however, to further process A in order to distill off the valuable lighter distillates, which are rerun into the light lubricating oils, a heavy bright residuum and a heavy distillate being also obtained. Heretofore the resulting heavy distillate, herein termed product B, has not been used because of its cloudy nature due to an extremely small percentage of soft wax end it is to the removal of such cloud that the Application filed september s, 1927. Serial No. 218,358.

present invention is directed, whereby the heavy distillates may be used for the purposes mentioned.

In carrying out this invention, a percentage of paraffin distillate containing some crystalline or paratfine wax is added to the distillate B and the mixture chilled to a low temperature whereupon it is passed through a filter press. \By so doing we have found that the crystalline wax forms a cake in the filter press which entraps the waxy cloudforming materials and separates them from In this manner a clear marketable oil is produced and one which may be rerun the oil.

being from 3 to 10 per cent. If desired,

parafiin distillate and a separate percentage of crystalline wax may both be used.

It is noted that the herein described meth- 0d of refiningoil will remove the cloud-forming material from any of the residuum oil distillates. V

Having fully described our invention, we claim The method of removing the cloud-forming materials from the hea distillates of resid uum oils consisting in a ding crystalline wax thereto within a substantial range of from 3 to 10 per cent, chilling the mixture and-separating the wax therefrom by filtering.

In testimony whereof we aflix our signatures.

CHARLES L. SUHR. WINFIELD S. ZEHRUNG. 

